#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main()
{
	float a = 1, b = 1, i, s = 0;
	for (i = 1; i <= 20; i++)
	{
		a = a + b;
		b = a - b;
		s += (a / b);
	}
	printf("sum=%f", s);
}